"If the existence of magical girls grants power, then give me the power to take revenge on you all—!" The enemy to be defeated is the world's guardian, the Magical Girl! A magical revenge action story of rage and vengeance begins!! In a world where magical girls save people and protect peace, Yura Nagare witnesses the sudden death of his one and only best friend, Kiki, in an accident. He suspects the involvement of Pure, a magical girl who was also at the scene, but no one in the world will listen to him. Wandering alone in search of the truth, Yura becomes convinced that the accident was caused intentionally by Pure. Yura confronts Pure but is met with a cold, uncharacteristic attitude for a magical girl and is not taken seriously. Faced with overwhelming power, Yura's rage at Kiki's death being treated so carelessly explodes, and he transforms into the monster, Waruimon—!!!